Pivotally balanced members



April 19, 1960 J. P. WATSON PIVOTALLY BALANCED MEMBERS Filed nay s, 195e 2 Sheets-Sheet 1 2 Sheets-Sheet 2 Filed May 6, 1958 JAMES R WATSON;

INVENTOR. HERZ/6 8 JESSUP,

A TTORNEKS.

gUnited States Patent O ce '2,933,580 PlvoTALLY BALANCED MEMBERS James P. Watson, Inglewood, Calif., assignor of one-half to Joe Davidson, South Gate, Calif.

Application May 6, 1958, Serial No. 733,449 11 Claims. (Cl. 20o- 166) This application relates to pivotally balanced members, and more particularly such members as are used in stepping switches and motors.

This invention relates to improvements in pivoted components of the type disclosed in co-pending applications Serial Nos. 607,422, now Patent No. 2,866,109, and 662,109, both tiled in the name of James P. Watson.

It is an object of this invention to provide improved electric brush means for switching electric current from one terminal to another. v

It is a further object of this invention to provide such a brush means or mechanism as will be completely balanced against accelerating forces or shocks from all directions.

It is the further object of this invention to provide electric brush mechanisms of such design that 'a large number of individual contacts may be grouped in a very small space.

It is another object of this invention to provide improved brush actuating means for separating a brush from a contact with a minimum of arc burning.

It is another object of this invention to provide irnproved means for mounting an electric brush so as to It is a further object of this invention to provide an improved brush mechanism uniquely suitable for use in :a rotary stepping switch wherein there is a double break Lin the circuit with each step of the switch.

It is a further object of this invention to provide a brush 'which may be easily manufactured and assembled and into which a pre-formed biasingspring may be easily inserted during assembly.

It is a further object of this invention to provide an `improved brush mechanism uniquely adapted to a rotary .stepping switch having means for inhibiting the creation lof short circuits between switch contacts by the gradual accumulation of conducting articles.

It is another object of this invention to provide an improved balanced pawl structure.

It is a further object of this invention to provide a pawl .structure which is easier and cheaper to manufacture .and assemble and which has increased longevity.

It is another object of this invention to provide a design for a resiliently biased pivoted pawl structure wherein a heavier spring wire may be used without proportionate increase in biasing torque, thereby permitting use of Astronger and longer lived spring components.

It is another object of this invention to provide a spring biased rotary balanced pawl wherein the biasing spring is free to perform its rotary bias on the pawl without being required to absorb an axial force to restrain the pawl in place on its mounting pin.

It is another object of this invention to provide a balanced, biased pawl wherein consistent operation may be obtained without maintenance of critical structural tolerances.

2,933,580 Patented Apr. 19, 1960 In accordance with these and other objects which will become apparent hereinafter, preferred forms of the present invention will now be described with reference to the accompanying drawings wherein:

Fig. 1 is a cross-sectional view of the brush mechanism of a stepping switch embodying the balanced brush of the present invention;

Fig. 2 is a fragmentary sectional view taken on line 2 2 in Fig. 1;

Fig. 3 is a sectional view taken on line 3 3 in Fig. l;

Fig. 4 is a perspective view showing one of the two complementary segments of the balanced brush;

Fig. 5 is a perspective view illustrating the balanced pawl of the present invention;

Fig. 6 is a section taken on line 6 6 in Fig. 5; and

Fig. 7 is a section taken on line 7 7 in Fig. 5.

Fig. 8 is a fragmentary plan view generally similar to Fig. 3, with the shaft and brushes removed, showing an alternative form of the present invention.

Referring to Fig. 1, there is shown a brush mechanism generally of the type shown in said Serial No. 662,109, and particularly Figs. 15 and 16 thereof, to which reference is made for a further understanding of the environn mental structure. v

The mechanism comprises a frame 21 carrying a pair of ring structures 22 and 23. The ring structure 23 comi prises a continuous conducting ring, while 22 comprises a plurality of discrete conducting contact segments 24 imbedded or otherwise mounted in the insulating frame 21.

As best seen in Fig. l, the frame is generally cylindrical and on the axis thereof is disposed a rotatively mounted shaft 26, to which is splined, or otherwise secured against rotation, a brush support means 27, including a projecting post 28, the end of which is formed as a sphere to constitute a ball support member 29.

The ring structures 22 and 23 are mounted axially adjacent to each other, as shown in Fig. 2, and have substantially the same internal diameter, thereby to be engaged by a balanced brush 31 composed of a pair of complementary segments 32 and 33 suitably secured t0- gether, as by rivets 34 and 36, but spaced apart by washers or spacers 37 and 38, circumjacent the rivets 34 and 36 respectively, and disposed between the two segments 32 and 33.

The two halves or segments of the brush 31 engage the respective rings 22 and 23 to transfer current from a given segment 24 in the ring 22 to the ring 23, or Vice versa.

The brush 31 is secured to the ball 29 by the provision of two facing complementary semi-sockets 42 and 43 (formed in parts 32 and 33) in which the ball 29 resides. The brush 31 is assembled over the ball 29 by placing the two segments 32 and 33 over the ball 29 and then riveting them together with the rivets 34 and 36.

The ball 29 is provided with a deep central slot 44 cut along a plane substantially midway between the two ring structures 22 and 23 as best seen in Fig. 2. The ball 29 is further provided with a central bore 46 passing therethrough substantially normal to the slot 44. Pressed into the bore 46 is a pin 47 which extends outwardly from each side of the ball 29 to reside in oversize bores 48 and 49 formed in the respective brush segments 32 and 33. The pin 47 is provided with a longitudinal slot 51 extending from one end thereof and fully into the ball slot 44, thereby providing passage for a biasing spring '52 formed into a general S shape, as shown in Fig. 1 and lying sub- -stantially in the plane of the ball slot 44. The spring 52 passes through the pin slot S1, as best seen in Fig. 1, and then is wrapped back partially around the pin 47 symmetrically. The respective ends of the spring extend away from the pin 47 and outside of the ball slot 44 to assenso Y w Y engagethe spacers 37 and 38, respectively, thereby to silient engagement with the respective ring structures 23 and 22.

It will be noted that-the universality, of the mounting provided by the ball 29 permits the brush to tilt slightly from side to side, thereby allowing Vthe faces 53 and 54 to engage rmly against the respective ring structures 23 and 22. This tilting is permitted by the fact that the bores 48 and 49 are appreciably larger than the vpin V47. The two ends of the pin 47 project outwardly into the brush 31 to limit the extent of transverse movement and thereby protect the springk 52 V,from being sheared oit or otherwise damaged during assemblyor disassembly of the mechanism.

The pin 47 has a diameterislightly'larger than the boreV 46 whereby a press tit is required to install the part,

thereby securing the pin 47 in the bore 46 against rotation. vit will be noted that aduplicate balanced brush structure is provided by forming posts 28' on the diametrically opposite side of shaft 26 (Figs; 1 and 3) thereby doubling thetoperating capacity of Vthe switch, as well as balancing the structure dynamically, another brush 31 being indicated mounted on an opposing post 28 and ball 29 and electrically connecting the ring structure 21 with a ring structure 25 similar to the ring structure`22.,

The segmental structure of the-brush 31 results in the spacers 37 and 3S performing simultaneously the'rnulti'ple functions of spacing the segments 32 and 33 ap`ait; carrying current from one segment to the other; acting as abutments or stops for the respective ends of -thes'pring 52; and serving to lift the engaging faces 53 and 54 away from the respective ring segments upon rotation of shaft 26 in a manner which will now be described. v Secured to the frame 21 and disposed 'in "a pl'anesubstantially coincident with the gapV 35 in the brush 31 is a circular non-conducting ring 56 having high portions 57 of relatively small radius and'low portions or recesses 58 of larger radius. As the brush 31 is carried in a circular path by rotation of the shaft 26, the lower spacer 37 engages a lobe or high area 57, as shown in Fig. 1, liftingthe engaging faces 53 and 54 radially inward away from the respective contacts 41 and 24 and rotating the brush 31 slightly on its ball mounting about the axis of the pin 47. The lift portion 57 of rail 56 is of surlicient height to cause the ends 53 and 54 to clear barriers 61 interposed transversely between adjacent contact segments 24. The segments 2.4 are thus, by virtue of the barriers 61, housed in separate individual pockets. The barrier 61 serves not only to inhibit arcing between adjacent segments 24 but also serves to block the 'interposition of tine bits of conducting debris which might otherwise cause a short circuit to appear between adjacent contacts. n

In the rotation of the shaft 26, after the brush ends 53 and 54 have cleared the barrier 61, the lift rail 56'is so cut that the spacer 37 drops into a recess S8 allowing the spring 52 to rmly bias the two ends of the brush into rm electrical engagement with the respective Vring structures 22 and 23.

The brush 31 is so shaped and'constructed that vitsV center of mass coincides substantially with'the center of the ball support member 29; thereby bouncing of the brush out of contact with the ring structures 22 and 23 under shock of high acceleration is obviated, because even under high acceleration there is no resultanttorque to rotate the brush aboutthe ball 29. Y

In Fig. 8 an alternative form of ring structure is illustrated, in which the parts carry corresponding numerals primed. replaced with -a ring structure 23 consisting of a plurality of individualdiscrete conducting contact segments 41 instead of a continuousring 4 1. TIt will be readily seen that this provides a double circuit break with veach open- In this vfigure, the ring structurev23 has been f ing of the switch, rather than theV single break which is provided when the ring 41 and'segm'ents 24 of Figs. 2 and 3 are employed. Y

Referring now to Figs. 5-7, the balanced pawl of the present invention will now be described.V This pawl is generally of the type ldescribed in said Patent No. 2,866,109, particularly at Figs. 114-14, and in said Serial No. 662,109, particularly Vat Figs. 6-10. Reference to these specifications is hereby made for a fuller understanding of the environment in whichy the pawl shown in Figs. 5-7 is employed.

Referringto these gures, 71 designates an arbor or pin forming a bearing for a pawl 72. The bearing portion of the pin 71 is ensmalled as shown at 73 where it passes Ythrough a bore (not shown) in the pawl 72, leaving a head 74 which restrains the pawl '72 against axial movement of the pin 7 1 in one direction. The pawl is prevented from moving axially in the other direction by bearing againsta suitable mounting member (not shown) in which the pin 71 is mounted; The head 74 of the pin` 71 Vhas a pair of axially spaced circumferential grooves 76 and 77. A diametral lslot on kerf 7S is also provided in the head, and the slot 78 has a sloping floor or bottom 79 communicating between the grooves 76 l 78and proceeds around the groove 76 as shown at S3 through anarc 'of approximately 270 and then leaves the groove 76-tangentially as shown at 84. lThe tip '86 ofthe wireis then engaged in a 'notch or pocket 87 formedin a lateral post 88 at one end of the pawl 72. The notch' or pocket 871isv in substantial alignment with the" circumferential groove 76 so that the lspring wire 81 may proceed directly from the pin 71 to the poel-iet 87 without further bending. Thisvobviates canting ofthe spring ends with consequent danger of chang.

The opposite tip 91 of the wire 81resides in a pocket or ynotch 92 formed in a post 93 vat the opposite end of thepawl 72,'which facesoppositely from the pocket 87. Thel pocket 92isspaced transversely ofthe pocket 87 so as to'lie in 'substantiallongitudinal" alignment with the other circurrir'erential groove- -77 from which the A"tip and 91 emerges. This`-end-is thus likewiseprevented from cantingand` chang.

That portion of the head'74 between the' groove 77 and the pawl 72A constitutes a flange 94 which serves to hold the pawl 72 against axial removal from the pin 71.

The ila'nge 94 obv'iates requiring the spring wire 81 to holdthe pawl 72 against axial removal from the pin 71, consequentlyv decreasing the loading on the spring and eliminating chafmg. The large wrap-around of approximately 270 Vprovided for each end ofthe spring 81 'permits the use ofheaviersp'ring'wire `and also makes the positioning ofthe kerf 78 much'less critical than-if partures ,maybe-made therefrom` within the scope of theginyention which'is therefore notto be limited tothe [details disclosed herein'but is toy be afforded-the full 'scope of the claims.

What isclainied is: l. Brus h mechanism comprising a frame, a pair of contact structures mounted'tofsaid'frame parallel andadjac'entjto each other, vbrush support means movably mounted' toy said frame and' disposedforfmovement' along said contact structures, said support means comprising a ball support member, brush means having socket means universally mounting said brush means to said ball support member, one side of. said brush means bearing against one of said structures, the other side of said brush means bearing against the other of said structures, said brush means and ball support member each having a bore therethrough transverse of said contacting structure, a pin residing in said bore and having an external diameter slightly smaller than the internal diameter of said bore through said brush means, said pin being secured in said ball support means against rotation and axial movement, and spring means engaging said pin and said brush means for biasing said brush means into engagement with said contact structures.

2. Mechanism in accordance with claim 1 wherein said pin has a longitudinal slot extending from one end thereof at least to the center of said ball support mem-- ber, said spring passing through said slot and -being wrapped at least partly around said pin and having its ends engaged by said brush means.

3. Mechanism in accordance with claim 1 wherein said ball support member has a central slot substantially normal to said bore and communicating with said bore, said spring passing through said slot.

4. Mechanism in accordance with claim l wherein said brush means is formed of two complementary segments having complementary semi-sockets assembled over said ball support member, a pair of spacer meansA between said segments on opposite sides of said ball support member, and means for securing said segments together around said ball support member, said spring means being disposed in the space between said segments.

5. Mechanism in accordance with claim 2 wherein said brush means is formed of two complementary segments having complementary semi-sockets assembled over said ball support member, spacer means between said segments on opposite sides of said ball support member, and means for securing said segments together around said ball support member, the ends of said spring engaging said spacer means to rotatively bias said brush means into engagement with said contact structures.

6. Mechanism in accordance with claim l wherein the center of mass of said brush means coincides substantially with the center of said ball support member.

7. Brush mechanism comprising a frame, a pair of ring structures mounted to said frame axially adjacent to each other and having substantially the same internal diameter, brush support means rotatably mounted to said frame and disopsed within said ring structures, said support means comprising a ball support member, brush means having socket means universally mounting said brush means to said ball support member, one side of said brush means bearing against one of said structures and the other side of said brush means bearing against the other of said structures, said brush means and ball support member each having a bore therethrough substantially parallel to the axis of said n'ng structures, a pin residing in said bores and having an external diameter slightly smaller than the internal diameter of said bores through said brush means, said pin being secured in said ball support means against rotation and axial movement, and spring means engaging said pin and said brush means for biasing said brush means into engagement with said ring structures.

8. Mechanism in accordance with claim 7 comprising in addition a ring-like lift rail disposed coaxially between said ring structures and fixed with respect thereto and means on said brush means for engaging said lift rail for supporting said brush means against the bias of said spring means during those portions of the rotation of said brush support means when said brush means is not in engagement with at least one of said ring structures.

9. Mechanism in accordance with claim 8 wherein the engagement of said engagement means on said brush means with said lift rail means servers to rotate said brush means radially inward away from said ring structures and subsequently permits said spring means to rotate said brush means radially outward back into engagement with said ring structures, during rotation of said brush support means.

l0. Mechanism in accordance with claim 9 wherein said brush means is formed of two complementary segments having complementary semi-sockets assembled over said ball support member, and wherein said lift rail engaging means on said brush means comprises one of a pair of spacer means between said segments disposed on opposite sides of said ball support member for spacing said segments apart, means for securing said segments together around said ball support member, the ends of said spring means engaging said spacer means to rotatively bias said brush means into engagement with said ring structures.

ll. Mechanism in accordance with claim 1 wherein said brush means is formed of two complementary segments having complementary semi-sockets assembled over said ball support member, a pair of spacers between said segments on opposite sides of said ball support member, and securing rivets passing through said spacers and securing said segments together around said ball support member.

References Cited in the le of this patent UNITED STATES PATENTS 1,371,590 Woodward Mar. 15, 1921 1,835,788 Knoop Dec. 8, 1931 2,691,086 Milne et al. Oct. 5, 1954 2,732,730 Sernaker Jan. 31, 1956 

